FERROMAGNETISM, DIMERIZATION, CHARGE AND SPIN-DENSITY WAVES IN QUASI-ONE-DIMENSIONAL ORGANIC POLYMERS - SELF-CONSISTENT MEAN-FIELD THEORY

We address the low temperature properties of quasi-one-dimensional org anic polymers, which may be described by a modified Anderson lattice-S u-Schrieffer-Heeger Hamiltonian. The condition and nature of various o rders, such as, the ferromagnetic order, the dimerization order, the c harge density wave order and the spin density wave order, are analyzed by a self-consistent mean field theory. Analytical results are obtain ed for a specific case. The topological structure of the chain leads t o a flatband structure of the energy band, which gives rise to a ferro magnetic order in the case of half filling at low temperatures. The on -site Coulomb repulsion enhances the ferromagnetic order, while the ne arest-neighbor interaction (V) suppresses both the ferromagnetic order and the dimerization, and leads to the charge density wave. The pi-d hybridization (t(d)) suppresses the dimerization, and does not affect the magnetization. The ferromagnetic order and dimerization order coex ist for weak t(d).